1. Field of the Invention
The present invention relates to an adjustable rod bending device, and more particularly to an adjustable rod bending device for bending a corrective spinal rod which is used in a surgical operation.
2. Description of the Related Art
A rod bender is used for bending a corrective spinal rod that can be used in a surgical operation for correcting the lumbar curvatures of the human body.
The closest prior art of which the applicant is aware is disclosed in U.S. Pat. No. 5,490,409, entitled "Adjustable Cam Action Rod Bender for Surgical Rods". However, the user has to exert a great force on the bender with two hands to bend the metallic rod, thereby causing inconvenience to the user. In addition, the metallic rod is locally bent to form an arc such that it has to fit a required curve by multiple small arcs whereby the curvature of the corrective spinal rod is determined based on the doctor's experience, such that when the doctor does not have efficient experience, the curvature of the corrective spinal rod is often not satisfactory such that he has to repeat the operations again and again, thereby decreasing the accuracy of bending the corrective spinal rod and probably yielding the material.
A second conventional rod bender in accordance with the prior art includes two elongated plates each containing a hole defined in one distal end whereby the corrective spinal rod has its two ends inserted into the hole of each of the two elongated plates. The two plates are then turned in opposite directions relative to each other, thereby bending the corrective spinal rod. However, the user has to exert a great force on the bender with two hands so as to bend the metallic rod, thereby causing inconvenience to the user. In addition, it is not easy to control the direction of force exerted on the two plates during the bending process, thereby greatly decreasing the accuracy of bending the corrective spinal rod. Further, the curvature of the corrective spinal rod is determined based on the doctor's experience, thereby decreasing the accuracy of bending the corrective spinal rod.
Other prior arts of which the applicant is aware are disclosed in U.S. Pat. No. 4,141,235, entitled "Hydraulic Bending Machine", U.S. Pat. No. 4,132,100, entitled "Hand-Operated Tool For Bending Pipes", U.S. Pat. No. 3,987,656, entitled "Pipe Bending Apparatus", and U.S. Pat. No. 4,910,984,entitled "Progressive Roller Bender", wherein the mentioned devices are used in non-medical applications.
The present invention has arisen to mitigate and/or obviate the disadvantage of the conventional rod bender.